Modem Architecture for Joint Source-Channel Decoding in VoLTE
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Solution Overview
Problem
Current communication systems, particularly in LTE, face challenges in improving voice quality and reducing packet loss rates without increasing power consumption or decreasing network capacity, as existing mechanisms for channel performance enhancement are limited and may have undesirable effects.
Innovation Solution
The implementation of a modem architecture that supports joint source channel decoding (JSCD) using multiple turbo decoders, which exploits parameter-based correlation and redundancy in voice data packets, allowing for improved channel capacity and data integrity through cooperative decoding of source and channel signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmissions are increased to improve channel performance, then data integrity is improved, but network capacity decreases
Solution Approach 1:
The patent applies preliminary action by performing source decoding before channel decoding in a joint source-channel decoding (JSCD) architecture. The source decoder reconstructs the original signal from received packets, and the channel decoder then corrects errors in the reconstructed signal. This preliminary source decoding step allows the system to achieve better data integrity with fewer retransmissions, thereby maintaining network capacity while improving reliability.
2Reliability
If coding rate is reduced to provide more redundancy, then data integrity is improved, but spectral efficiency decreases
Solution Approach 1:
The patent merges source decoding and channel decoding into a unified joint source-channel decoding (JSCD) architecture. Instead of treating source coding and channel coding as separate stages, the system combines them to exploit both source signal characteristics and channel code properties simultaneously. This merging allows the system to achieve better data integrity without requiring excessive redundancy, thereby maintaining spectral efficiency while improving reliability.
3Reliability
If modulation scheme is changed to send fewer bits per symbol, then data integrity is improved, but spectral efficiency decreases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the decoding strategy based on channel conditions and packet characteristics. The joint source-channel decoder can adaptively change operational parameters such as decoding iteration counts, threshold values, and resource allocation to optimize the balance between data integrity and spectral efficiency. This allows the system to maintain high spectral efficiency while achieving improved data integrity through intelligent parameter optimization rather than simply reducing bits per symbol.
4Reliability
If joint source channel decoding is implemented to improve voice quality, then packet loss rate decreases, but device complexity increases
Solution Approach 1:
The patent segments the joint source-channel decoding process into distinct functional modules: a source decoder module that reconstructs the signal from received packets, a channel decoder module that corrects errors in the reconstructed signal, and an integration module that coordinates their operation. This segmentation allows the complex JSCD functionality to be implemented as separate, manageable components, reducing overall device complexity while maintaining the packet loss rate improvements provided by joint decoding.
Data Source
AI summary
A modem architecture that supports the application of joint source channel decoding (JSCD). The modem architecture includes two channel decoders, one of which is modified to provide improved signal quality. The modem architecture further includes transparent network layers that enable the passage of data from one layer to another layer. For example, the modem architecture enables the passage soft bits, when available, from a physical layer to an application layer. The soft bits may be utilized for JSCD, packet loss concealment, or other applications. The modem architecture enables encryption and decryption of data to incorporate extrinsic information in operating JSCD.